BIOL 2402 EXAM 1 STUDY GUIDE 2026 UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS
Question:
1. What is the difference between the nervous and endocrine systems in terms of speed and duration of
response?
Answer:
The nervous system responds quickly (milliseconds) but its effects are short-lived, while the endocrine
system responds slowly (seconds to days) but its effects are longer-lasting.
Question:
2. What is the function of the endocrine system?
Answer:
It coordinates and integrates activity of body cells, influences metabolic activities via hormones, and
controls reproduction, growth/development, fluid balance, metabolism, and body defenses.
Question:
3. What is the difference between an exocrine gland and an endocrine gland?
Answer:
Exocrine glands produce nonhormonal substances and have ducts to carry secretions to a membrane
surface, while endocrine glands produce hormones and lack ducts, secreting their products into the
bloodstream.
Question:
4. List the primary endocrine organs.
Answer:
Pituitary, thyroid, parathyroid, adrenal, and pineal glands; the hypothalamus is also a neuroendocrine
organ.
Question:
5. Name three organs that have both endocrine and exocrine functions.
Answer:
Pancreas, gonads (ovaries/testes), and the placenta.
Question:
6. Besides the major endocrine organs, what other tissues/organs produce hormones?
Answer:
Adipose cells, thymus, and cells in the walls of the small intestine, stomach, kidneys, and heart.
Question:
7. Define hormone, autocrine, and paracrine.
Answer:
Hormones are long-distance chemical signals that travel in blood or lymph; autocrines exert effects on the
same cells that secrete them; paracrines affect cells other than those that secrete them.
,Question:
8. What are the two major chemical classes of hormones?
Answer:
1. Amino acid-based hormones (amino acid derivatives, peptides, proteins). 2. Steroids (synthesized from
cholesterol).
Question:
9. What is a third class of local messengers that some scientists consider hormones?
Answer:
Eicosanoids.
Question:
10. What is a target cell?
Answer:
Tissues that have receptors for a specific hormone; only cells with the specific receptor for that hormone
will be affected.
Question:
11. List five ways hormones can alter target cell activity.
Answer:
1. Alter plasma membrane permeability. 2. Stimulate synthesis of enzymes or proteins. 3. Activate or
deactivate enzymes. 4. Induce secretory activity. 5. Stimulate mitosis.
Question:
12. What are the two main mechanisms by which hormones act on target cells?
Answer:
1. Water-soluble hormones act on plasma membrane receptors via second-messenger systems.
2. Lipid-soluble hormones act on intracellular receptors that directly activate genes.
Question:
13. Describe the five steps of the cyclic AMP (cAMP) second-messenger mechanism.
Answer:
1. Hormone binds to receptor. 2. Receptor activates a G protein. 3. G protein activates adenylate cyclase. 4.
Adenylate cyclase converts ATP to cAMP. 5. cAMP activates protein kinases, leading to a cellular
response.
Question:
14. How is the cAMP signal turned off?
Answer:
The enzyme phosphodiesterase rapidly degrades cAMP.
Question:
15. Describe the PIP■-calcium signaling mechanism.
Answer:
1. Hormone binds to receptor, activating a G protein. 2. G protein activates phospholipase C.
3. Phospholipase C splits PIP■ into DAG and IP■.
4. Ca²■ is released from intracellular stores.
, Question:
16. How do lipid-soluble hormones act on their target cells?
Answer:
They diffuse into the target cell, bind to an intracellular receptor, and the hormone-receptor complex enters
the nucleus to initiate gene transcription.
Question:
17. On what three factors does the degree of target cell activation depend?
Answer:
1. Blood levels of the hormone. 2. Relative number of receptors on the target cell. 3. Affinity of binding
between the receptor and hormone.
Question:
18. Define up-regulation and down-regulation.
Answer:
Up-regulation: Target cells form more receptors in response to low hormone levels. Down-regulation:
Target cells lose receptors in response to high hormone levels.
Question:
19. How do hormones with different effects interact on the same target cell?
Answer:
Permissiveness: One hormone cannot exert its effects without another present. Synergism: More than one
hormone amplifies the same effect. Antagonism: One hormone opposes another.
Question:
20. What is the primary mechanism that controls blood hormone levels?
Answer:
Negative feedback systems.
Question:
21. What are the three types of stimuli that trigger endocrine glands to release hormones?
Answer:
1. Humoral stimuli. 2. Neural stimuli. 3. Hormonal stimuli.
Question:
22. Give an example of a humoral stimulus.
Answer:
Low concentration of Ca²■ in the blood stimulates the parathyroid glands to release parathyroid hormone.
Question:
23. Give an example of a neural stimulus.
Answer:
Sympathetic nervous system fibers stimulate the adrenal medulla to secrete epinephrine and
norepinephrine.
Question:
24. Give an example of a hormonal stimulus.
QUESTIONS AND CORRECT ANSWERS
Question:
1. What is the difference between the nervous and endocrine systems in terms of speed and duration of
response?
Answer:
The nervous system responds quickly (milliseconds) but its effects are short-lived, while the endocrine
system responds slowly (seconds to days) but its effects are longer-lasting.
Question:
2. What is the function of the endocrine system?
Answer:
It coordinates and integrates activity of body cells, influences metabolic activities via hormones, and
controls reproduction, growth/development, fluid balance, metabolism, and body defenses.
Question:
3. What is the difference between an exocrine gland and an endocrine gland?
Answer:
Exocrine glands produce nonhormonal substances and have ducts to carry secretions to a membrane
surface, while endocrine glands produce hormones and lack ducts, secreting their products into the
bloodstream.
Question:
4. List the primary endocrine organs.
Answer:
Pituitary, thyroid, parathyroid, adrenal, and pineal glands; the hypothalamus is also a neuroendocrine
organ.
Question:
5. Name three organs that have both endocrine and exocrine functions.
Answer:
Pancreas, gonads (ovaries/testes), and the placenta.
Question:
6. Besides the major endocrine organs, what other tissues/organs produce hormones?
Answer:
Adipose cells, thymus, and cells in the walls of the small intestine, stomach, kidneys, and heart.
Question:
7. Define hormone, autocrine, and paracrine.
Answer:
Hormones are long-distance chemical signals that travel in blood or lymph; autocrines exert effects on the
same cells that secrete them; paracrines affect cells other than those that secrete them.
,Question:
8. What are the two major chemical classes of hormones?
Answer:
1. Amino acid-based hormones (amino acid derivatives, peptides, proteins). 2. Steroids (synthesized from
cholesterol).
Question:
9. What is a third class of local messengers that some scientists consider hormones?
Answer:
Eicosanoids.
Question:
10. What is a target cell?
Answer:
Tissues that have receptors for a specific hormone; only cells with the specific receptor for that hormone
will be affected.
Question:
11. List five ways hormones can alter target cell activity.
Answer:
1. Alter plasma membrane permeability. 2. Stimulate synthesis of enzymes or proteins. 3. Activate or
deactivate enzymes. 4. Induce secretory activity. 5. Stimulate mitosis.
Question:
12. What are the two main mechanisms by which hormones act on target cells?
Answer:
1. Water-soluble hormones act on plasma membrane receptors via second-messenger systems.
2. Lipid-soluble hormones act on intracellular receptors that directly activate genes.
Question:
13. Describe the five steps of the cyclic AMP (cAMP) second-messenger mechanism.
Answer:
1. Hormone binds to receptor. 2. Receptor activates a G protein. 3. G protein activates adenylate cyclase. 4.
Adenylate cyclase converts ATP to cAMP. 5. cAMP activates protein kinases, leading to a cellular
response.
Question:
14. How is the cAMP signal turned off?
Answer:
The enzyme phosphodiesterase rapidly degrades cAMP.
Question:
15. Describe the PIP■-calcium signaling mechanism.
Answer:
1. Hormone binds to receptor, activating a G protein. 2. G protein activates phospholipase C.
3. Phospholipase C splits PIP■ into DAG and IP■.
4. Ca²■ is released from intracellular stores.
, Question:
16. How do lipid-soluble hormones act on their target cells?
Answer:
They diffuse into the target cell, bind to an intracellular receptor, and the hormone-receptor complex enters
the nucleus to initiate gene transcription.
Question:
17. On what three factors does the degree of target cell activation depend?
Answer:
1. Blood levels of the hormone. 2. Relative number of receptors on the target cell. 3. Affinity of binding
between the receptor and hormone.
Question:
18. Define up-regulation and down-regulation.
Answer:
Up-regulation: Target cells form more receptors in response to low hormone levels. Down-regulation:
Target cells lose receptors in response to high hormone levels.
Question:
19. How do hormones with different effects interact on the same target cell?
Answer:
Permissiveness: One hormone cannot exert its effects without another present. Synergism: More than one
hormone amplifies the same effect. Antagonism: One hormone opposes another.
Question:
20. What is the primary mechanism that controls blood hormone levels?
Answer:
Negative feedback systems.
Question:
21. What are the three types of stimuli that trigger endocrine glands to release hormones?
Answer:
1. Humoral stimuli. 2. Neural stimuli. 3. Hormonal stimuli.
Question:
22. Give an example of a humoral stimulus.
Answer:
Low concentration of Ca²■ in the blood stimulates the parathyroid glands to release parathyroid hormone.
Question:
23. Give an example of a neural stimulus.
Answer:
Sympathetic nervous system fibers stimulate the adrenal medulla to secrete epinephrine and
norepinephrine.
Question:
24. Give an example of a hormonal stimulus.
